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The speed of an electric fan is reduced with the help of a regulator . What will happen in the energy consumption ? |
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Answer» Solution :If an ELECTRIC fan of resistance R runs under potential difference V for time t , then work done , `W=I^(2)Rt=(I^(2)R^(2)t)/(R)=(V^(2)t)/(R)` To REDUCE the speed , some resistance , say`R_(1)` is added in series through a regulator . So the potential difference at the two ends of the combination of R and `R_(1)` is V . So , work done in time `t,W_(1)=(V^(2)t)/(R+R_(1))` EVIDENTLY , `W_(1)` is less than W . So , energy CONSUMPTION decreases. |
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